Method for treating a variety of wastewater streams

Abstract

The present invention is a wastewater treatment method using dried BOF slag and hydrogen peroxide, wherein hydrogen peroxide is oxidized to generate hydroxyl radicals that reacts with soluble metal contaminants in the sludge such that these contaminants can be adsorb on the catalyst particles and/or eliminated from the wastewater stream by separation techniques. The process can use catalytic oxidation for soluble metals removal. In addition, catalytic oxidation can produce a filtered water saturated with Oxygen and higher in pH resulting in enhanced precipitation of soluble metals when softening agents, such as Sodium Carbonate, are added in a subsequent processing step. Another embodiment of the present invention is a method using ferrous sulfate for removing soluble metals in wastewater, followed by Catalytic Oxidation to remove soluble Fe without addition of metal salts, and removing sulfates by adding Barium Carbonate.

What is claimed is: 
     
       1. A method of treating wastewater for the removal of metals from the wastewater, the method comprising steps of:
 adding the wastewater, dried Basic Oxygen Furnace (BOF) slag, and hydrogen peroxide (H 2 O 2 ) to a Catalytic Oxidation reactor unit and stirring to create a first catalytic metal slurry, wherein soluble metals in solution are absorbed onto a surface of the BOF slag; 
 transferring the first catalytic metal slurry to a first separation unit and subjecting the first catalytic metal slurry to a first solid-liquid separation process to create (i) a first treated wastewater and (ii) a catalytic metal sludge; 
 transferring the first treated wastewater to a metal precipitation unit; 
 adding a Carbonate to the metal precipitation unit and stirring to create a carbonate metal slurry; and 
 transferring the carbonate metal slurry to a second separation unit and subjecting the carbonate metal slurry to a second solid-liquid separation process to create (i) a second treated wastewater and (ii) a filtered sludge, 
 wherein the second treated wastewater contains less metals than the wastewater and is reusable for an industrial operation. 
 
     
     
       2. The method according to  claim 1 , further comprising steps of:
 transferring the first treated wastewater to a metal desorption unit before the step of metal precipitation according to  claim 1 ; 
 adding de-ionized DI water to the first treated wastewater in the metal desorption unit and stirring to create a barium/iron rich slurry; 
 transferring the barium/iron rich slurry to an intermediate separation unit and subjecting the barium/iron slurry to an intermediate solid-liquid separation process to create (i) a filtered water containing Barium and Iron and (ii) a wet BOF Slag; and 
 transferring the filtered water containing Barium and Iron to the metal precipitation unit for precipitation of the filtered water containing Barium and Iron according to the step of metal precipitation of  claim 1 . 
 
     
     
       3. The method according to  claim 1 , wherein the step of adding the wastewater, dried Basic Oxygen Furnace (BOF) slag, and hydrogen peroxide (H 2 O 2 ) to a Catalytic Oxidation reactor unit comprises:
 adding a Dried Basic Oxygen Furnace (BOF) slag to wastewater ratio=1-300 g/L; 
 adding a H 2 O 2  Concentration=0.1-2M solution, and 
 adding a Dried Basic Oxygen Furnace (BOF) slag to H 2 O 2  (100%) ratio=0.25-7 g/g. 
 
     
     
       4. The method according to  claim 1 , wherein the step of adding a Carbonate to the metal precipitation unit comprises adding a Carbonate to wastewater ratio=1-100 g/L. 
     
     
       5. The method according to  claim 4 , wherein the Carbonate is Na 2 CO 3 . 
     
     
       6. The method according to  claim 1 , wherein the step of adding the wastewater, dried Basic Oxygen Furnace (BOF) slag, and hydrogen peroxide (H 2 O 2 ) to a Catalytic Oxidation reactor unit comprises:
 adding a Dried Basic Oxygen Furnace (BOF) slag to wastewater ratio=20-30 g/L; 
 adding a H 2 O 2  Concentration=3-7M solution, and 
 adding a Dried Basic Oxygen Furnace (BOF) slag to H 2 O 2  (100%) ratio=5.3-7.5 g/g. 
 
     
     
       7. The method according to  claim 1 , wherein the step of adding the Carbonate to the metal precipitation unit comprises adding a Carbonate to wastewater ratio=40-45 g/L. 
     
     
       8. The method according to  claim 4 , wherein the Carbonate is Na 2 CO 3 . 
     
     
       9. The method according to  claim 1 , wherein the step of adding the wastewater, dried Basic Oxygen Furnace (BOF) slag, and hydrogen peroxide (H 2 O 2 ) to a Catalytic Oxidation reactor unit comprises:
 adding a Dried Basic Oxygen Furnace (BOF) slag to wastewater ratio=25 g/L; 
 adding a H 2 O 2  Concentration=0.1M solution, and 
 adding a Dried Basic Oxygen Furnace (BOF) slag to H 2 O 2  (100%) ratio=7 g/g. 
 
     
     
       10. The method according to  claim 1 , wherein the step of adding the Carbonate to the metal precipitation unit comprises adding a Carbonate to wastewater ratio=43.22 g/L. 
     
     
       11. The method according to  claim 4 , wherein the Carbonate is Na 2 CO 3 . 
     
     
       12. The method according to  claim 2 , wherein the step of adding the wastewater, dried Basic Oxygen Furnace (BOF) slag, and hydrogen peroxide (H 2 O 2 ) to a Catalytic Oxidation reactor unit comprises:
 adding a Dried Basic Oxygen Furnace (BOF) slag to wastewater ratio=250 g/L; 
 adding a H 2 O 2  Concentration=1.35M solution, and 
 adding a Dried Basic Oxygen Furnace (BOF) slag to H 2 O 2  (100%) ratio=3 g/g. 
 
     
     
       13. The method according to  claim 2 , wherein the step of adding de-ionized DI water comprises adding a De-ionized DI water to the Catalyst Metal Sludge ratio=0.25-2 mL/g. 
     
     
       14. The method according to  claim 1 , wherein the second treated wastewater contains at least 95% less Iron than the wastewater. 
     
     
       15. The method according to  claim 1 , wherein the second treated wastewater contains at least 95% less Calcium than the wastewater. 
     
     
       16. The method according to  claim 1 , wherein the second treated wastewater contains at least 90% less Barium than the wastewater. 
     
     
       17. The method according to  claim 1 , wherein the second treated wastewater contains at least 75% less Strontium than the wastewater. 
     
     
       18. The method according to  claim 1 , wherein the second treated wastewater contains at least 35% less Magnesium than the wastewater. 
     
     
       19. The method according to  claim 1 , wherein the second treated wastewater contains at least 85% less Total Suspended Solids than the wastewater. 
     
     
       20. The method according to  claim 1 , wherein the second treated wastewater contains at least 85% less Hardness than the wastewater. 
     
     
       21. The method according to  claim 2 , wherein the second treated wastewater contains at least 95% less Iron than the wastewater. 
     
     
       22. The method according to  claim 2 , wherein the second treated wastewater contains at least 45% less Barium than the wastewater. 
     
     
       23. The method according to  claim 1 , wherein the second treated wastewater contains at least 95% less Iron, at least 95% less Calcium, at least 90% less Barium, at least 75% less Strontium, at least 35% less Magnesium, at least 85% less Total Suspended Solids, and at least 85% less Hardness than the wastewater. 
     
     
       24. The method according to  claim 2 , wherein the second treated wastewater contains at least 95% less Iron and at least 45% less Barium than the wastewater. 
     
     
       25. A method of treating wastewater for the removal of metals from the wastewater, the method comprising steps of:
 adding the wastewater and Ferrous Sulfate (FeSO 4 ) to a metal precipitation unit and stirring to create a metal sulfate slurry; 
 transferring the metal sulfate slurry to a first separation unit and subjecting the metal sulfate slurry to a first solid-liquid separation process to create a first treated wastewater and a filtered sludge; 
 transferring the first treated wastewater to a Catalytic Oxidation reactor unit; 
 adding Dried Basic Oxygen Furnace (BOF) slag, Hydroxides, hydrogen peroxide (H 2 O 2 ) to the Catalytic Oxidation reactor unit and stirring to create a catalytic metal slurry; 
 transferring the catalytic metal slurry to a second separation unit and subjecting the catalytic metal slurry to a solid-liquid separation process to create a second treated wastewater and a catalytic metal sludge, 
 transferring the second treated wastewater to a sulfates precipitation unit; 
 adding Barium Carbonate (BaCO 3 ) to the sulfates precipitation unit and stirring to create a barium sulfate slurry; 
 transferring the barium sulfate slurry to a third separation unit and subjecting the barium sulfate slurry to the solid-liquid separation process to create a third treated wastewater and a filtered sludge, 
 wherein the third treated wastewater contains less metals than the wastewater and is reusable for an industrial operation. 
 
     
     
       26. The method according to  claim 25 , wherein the Hydroxides is NaOH. 
     
     
       27. The method according to  claim 25 , wherein the step of adding the wastewater and Ferrous Sulfate (FeSO 4 ) to a metal precipitation unit comprises adding a FeSO 4  to wastewater ratio=2-120 g/L. 
     
     
       28. The method according to  claim 25 , wherein the step of adding the wastewater and Ferrous Sulfate (FeSO 4 ) to a metal precipitation unit comprises adding a FeSO 4  to wastewater ratio=45-70 g/L. 
     
     
       29. The method according to  claim 25 , wherein the step of adding the wastewater and Ferrous Sulfate (FeSO 4 ) to a metal precipitation unit comprises adding a FeSO 4  to wastewater ratio=48.66 g/L. 
     
     
       30. The method according to  claim 25 , wherein the step of adding Dried Basic Oxygen Furnace (BOF) slag, Hydroxides, hydrogen peroxide (H 2 O 2 ) to the Catalytic Oxidation reactor unit comprises:
 adding a Dried Basic Oxygen Furnace (BOF) slag to wastewater ratio=1-300 g/L, 
 adding a H 2 O 2  Concentration=0.1-2M solution, 
 adding a Dried Basic Oxygen Furnace (BOF) slag to H 2 O 2  (100%) ratio=0.25-7 g/g, and 
 a Hydroxides to Wastewater ratio=5-100 g/L. 
 
     
     
       31. The method according to  claim 25 , wherein the step of adding Dried Basic Oxygen Furnace (BOF) slag, Hydroxides, hydrogen peroxide (H 2 O 2 ) to the Catalytic Oxidation reactor unit comprises:
 adding a Dried Basic Oxygen Furnace (BOF) slag to wastewater ratio=250 g/L, 
 adding a H 2 O 2  Concentration=0.97M solution, 
 adding a Dried Basic Oxygen Furnace (BOF) slag to H 2 O 2  (100%) ratio=7 g/g, and 
 adding a Hydroxides to Wastewater ratio=52.63 g/L. 
 
     
     
       32. The method according to  claim 25 , wherein the step of adding Barium Carbonate (BaCO 3 ) to the sulfates precipitation unit comprises adding a BaCO 3  to Wastewater ratio=2.5-10 g/L. 
     
     
       33. The method according to  claim 25 , wherein the step of adding Barium Carbonate (BaCO 3 ) to the sulfates precipitation unit comprises adding a BaCO 3  to Wastewater ratio=3-3.5 g/L. 
     
     
       34. The method according to  claim 25 , wherein the step of adding Barium Carbonate (BaCO 3 ) to the sulfates precipitation unit comprises adding a BaCO 3  to Wastewater ratio=3.3 g/L. 
     
     
       35. The method according to  claim 25 , wherein the third treated wastewater contains at least 95% less Iron than the wastewater. 
     
     
       36. The method according to  claim 25 , wherein the third treated wastewater contains at least 95% less Calcium than the wastewater. 
     
     
       37. The method according to  claim 25 , wherein the third treated wastewater contains at least 95% less Barium than the wastewater. 
     
     
       38. The method according to  claim 25 , wherein the third treated wastewater contains at least 95% less Strontium than the wastewater. 
     
     
       39. The method according to  claim 25 , wherein the third treated wastewater contains at least 95% less Magnesium than the wastewater. 
     
     
       40. The method according to  claim 25 , wherein the third treated wastewater contains at least 75% less Total Suspended Solids than the wastewater. 
     
     
       41. The method according to  claim 25 , wherein the third treated wastewater contains at least 95% less Hardness than the wastewater. 
     
     
       42. The method according to  claim 25 , wherein the third treated wastewater contains at least 95% less Iron, at least 95% less Calcium, at least 95% less Barium, at least 95% less Strontium, at least 95% less Magnesium, at least 75% less Total Suspended Solids, and at least 95% less Hardness than the wastewater.